Recycled Lactobacillus pentosus biomass can regenerate biosurfactants after various fermentative and extractive cycles

Abstract

In this work cells of Lactobacillus pentosus, growing on 20 g/L of glucose for 15 h at 31 • C, were subjected to sequential fermentation and extraction processes with phosphate buffered saline (PBS) in order to study the capacity of L. pentosus to regenerate biosurfactants after various fermentative and extractive cycles. After a first extraction cycle, it was observed that, in absence of nutrients, L. pentosus, dissolved in PBS, does not have the capacity to induce the formation of new biosurfactants, although the extraction process almost did not affect the cell viability. However, when this biomass was recycled and subjected to three sequential fermentative processes, in presence of fresh fermentative medium, with their respective extraction procedures, L. pentosus cells recovered its capacity to produce more biosurfactants, observing an increase in the biosurfactant/biomass ratio, achieving a total biosurfactant concentration of 27 g/L, being the highest reported at the moment in the literature for L. pentosus.

Reuse of Immobilized Weissella cibaria PN3 for Long-Term Production of Both Extracellular and Cell-Bound Glycolipid Biosurfactants

“…For example, Joy et al (2019) reported a maximum overall rhamnolipid production of 19.35 g/L from Achromobacter sp. PS1 after five cycles of sequential fill and draw approach during 18-day period, and Bustos et al (2018) showed that Lactobacillus pentosus biomass produced had an overall biosurfactant production of only 2.7 g/L after three cycles during a 45-h period. It is possible to apply immobilized Weissella cibaria PN3 cells in a scale-up system for long-term biosurfactant production.…”

“…The cell pellets were washed with 0.85% NaCl, while the supernatant was extracted with 10% (v/v) hexane to remove residual oil. The cell-bound biosurfactant was recovered by resuspending the cell pellets in methanol with shaking for 1 h. Although, most researchers use PBS to obtain cell-bound biosurfactants from cell pellets (Bustos et al, 2018), our preliminary results showed that almost all the biosurfactant in the cell pellet fraction could be extracted with methanol, while PBS (at pH 7.0 and 8.0) and chloroform gave lower yields (Supplementary Figure 3). The hydrophilicity of Weissella cibaria PN3 cell-bound biosurfactant was probably different from that of other LAB biosurfactants.…”

“…The biosurfactants from LABs have been classified into several groups, such as glycolipopeptide from Lactobacillus pentosus ( Vecino et al, 2015 ), glycolipid from Lactobacillus helveticus MRTL91 ( Sharma et al, 2014 ), glycoprotein from L. plantarum ( Madhu and Prapulla, 2014 ) and lipoprotein from Pediococcus dextrinicus SHU1593 ( Ghasemi et al, 2019 ). The commercial application of LAB biosurfactants is limited by the low biosurfactant yield and inadequate information on their structural composition and functional characteristics ( Bustos et al, 2018 ). The biosurfactant yields from LABs are usually in the range of mg per liter ( Sharma et al, 2014 , 2015 ).…”

“…Another approach for increasing total biosurfactant yields is to reuse the bacterial biomass in sequential fermentation. Bustos et al (2018) found that L. pentosus cells can be subjected to 3 fermentation cycles after extracting the cell-bound biosurfactants with phosphate buffered saline. In addition, the rhamnolipid yield of Achromobacter sp.…”

Thermal Analysis of Nigerian Oil Palm Biomass with Sachet-Water Plastic Wastes for Sustainable Production of Biofuel

“…The current situation of the power generation requires a new approach to impede the growing threats of CO 2 emissions from gen-sets. In this context, alternative energy generation from local biomass could be one of the most viable solutions to instantly minimize the intake of fossil fuels to reduce environmental complications [6][7][8].…”